Hi, Bharath is right that it still fails when only one slot is left. But I think v1 still fixes the case where all slots are taken.
That said, running out of DSM slots seems very rare. I have never seen it happen, and this thread is the first time I learned the limit exists. If we think it is a real problem, how about reserving some DSM slots just for vacuum? That would be similar to how autovacuum_worker_slots gives autovacuum workers their own pool. Thanks, Shihao
